What is the source for that information? How do we know Pegula wanted Mahomes?
I don't really think that is the case. Allen showed flashes even from his rookie season. A couple of his best games ever were from his rookie season. He always had that "it," factor. He passed the eye test even when his stats didn't completely agree.
Allen has improved a lot, but he always had what it took. You could say the franchise took a risk, and that is true, but the draft is always a risk. Even the top prospects are a risk. The failure rate for 1st round draft picks is very high.